DE-OS 39 07 980 discloses a windscreen washer system with a spraying device comprising several nozzles made of elastic material. Because the direction of the jet coming from the nozzle elements should be adjustable, they are contained in movable nozzle units arranged in a common nozzle housing. The movability of the nozzle elements requires a relatively complicated structure of the nozzle housing.
DE-OS 35 03 496 discloses a nozzle housing with a nozzle that is achieved by a simple bore through the wall of the nozzle housing, the bore being then connected to a central channel. The execution of the bores requires a considerable expenditure e of time and work. Furthermore, the bores must have a certain diameter and it is difficult to clean them when they are clogged.
DE-OS 18 00 013 discloses a nozzle housing made of elastic material so that the nozzle can expand under the pressure of the cleaning liquid to eject dirt particles. The function of this nozzle housing is similar to that described in DE-OS 30 07 980, but is applicable for a single nozzle.
According to U.S. Pat. No. 3,940,068 the nozzles for a spraying device are formed by inserting a cover-type nozzle element into the nozzle housing which represents the completing part of the channel walls being provided as open channels on the surface of the nozzle housing. The advantage of this configuration is in particular, that the channels can be executed in a comparatively simple manner and that it is possible to clean the outlets of the nozzles without difficulty by simply removing the nozzle element for a short time. A disadvantage of the nozzle housing known from U.S. Pat. No. 3,940,068 is that the nozzles have a fixed diameter and that it is not possible to clean them when the nozzle element is fastened in the nozzle housing in order to prevent an inadvertent removal.
Aim of the present invention is to create a nozzle by simple means the aperture of which depends on the pressure of the sprayed cleaning liquid. The particular advantage of such nozzles is that they are self-cleaning since the obstructing particles can be ejected through the opening nozzle due to the increasing pressure of the obstructing particles. Furthermore, such nozzles can be configured in such a way that they are closed in normal conditions so that the antifreeze cannot evaporate and any ice formations which form thereon are blown off under the pressure of the cleaning liquid by means of the movable nozzle element.
The present invention consists of a part of the nozzle being formed by the housing itself, while the movable part of the nozzle is formed by a section of the elastic member deforming under the pressure of the cleaning liquid. Thus it is possible to form one or even several nozzles only by means of a single elastic member, preferably an elastic seal, which abuts on a surface, particularly the edge of the aperture of the nozzle housing, and opens the way for the liquid by deforming under the pressure of the cleaning liquid.
With this embodiment of the present invention, the same effect as described in DE-OS 39 07 980 with regard to the duckbill-type nozzle elements is achieved by simple means. If a major surface shall be moistened with liquid for the washing procedure it is known to arrange several nozzles at a certain distance from each other on the nozzle housing (see, for example, DE-OS 39 07 980).
Thus, a single elastic member, preferably in a flat seal, forms a part of all side walls of all desired nozzles. According to the present invention, several nozzles can therefore be formed by means of a single seal which results in a relatively simple and cheap construction of a multiple nozzle unit.
The single nozzles can be distributed circularly on the circumference of a nozzle element. A particularly simple construction is achieved by the present invention due to the cylindrical shape, the nozzle elements can be arranged on the divided circumferential surface of the body.
In a preferred embodiment the parts of the nozzle housing are coupled together, consisting of retaining member and cover, simply by screw-type or lock-type engagement.
A further simplification can be achieved by providing the cover with a fitting for the fastening of a hose pipe which delivers the cleaning liquid.
Since the windshield to be washed should be moistened especially in the area of the wipers, it is recommended, as already known, to fasten the nozzle housing on the wiper arm. The two locking arms of the clip can embrace directly the wiper arm, as described in U.S. Pat. No. 3,940,068. As additional safety device a web can be used in order to prevent the housing from sliding from the wiper arm, which therefore serves at the same time as additional safety device for the snap-in connection. Even this web can be fastened in a snap-in connection with the locking arms of the housing. The web itself can be formed in one piece, yet flexible, on one of the locking arms. It is also possible to fasten the nozzle housing on the motor hood.
As already mentioned, single areas of the seal can be assigned to single nozzles of a multiple nozzle. The areas of the seal not directly forming a part of the nozzle are retained by projections of the nozzle housing in such a way that the are preloaded preferably in the closing direction of the nozzle. In a preferred embodiment, the nozzle housing is provided with recesses adjacent to the apertures. This feature allows the aperture of the nozzle to be opened sufficiently despite the compressed seal. According to this, space is left with regard to the area of the housing positioned near the nozzle aperture, so that the elastic element can freely move in order to open the nozzle diameter.
In another preferable embodiment, the nozzle unit is provided with a central channel, preferably connected with the fitting, from which single channels extend leading to the respective nozzle. Preferably, the channels extend essentially perpendicular to the outer surface. According to another aspect of the present invention the web and/or the cover includes projections with mating abutment areas for clamping the retaining member formed as seal and thus provide for the preload necessary to close the apertures in case of unpressurized washing liquid.
A particularly simple manner of fastening the cover on the retaining member is accomplished by including snap-in projections in the bars of the cover.
An increase of the stability of the nozzle unit is described in the present invention. The connection of the two elements of the nozzle unit can be achieved in a simple way. In preferred configurations the seal which is common to all nozzles is positioned flatly in the plane of the nozzles. Another possibility, described in the favorable development of the present invention and consists in positioning the seal at a certain angle with regard to the channels leading to the nozzle apertures, preferably around the circumferential surface of the cylindrical housing.
In another favorable embodiment, the seal is structured in such a way that it extends, in its border area, at a certain angle to the central area of the sealing surface. In this case, the areas of the seal being under self-preload can serve for closing the nozzle apertures.